We have developed a preliminary worldwide list of fossil diatoms mainly from freshwater (non-marine) habitats. The orders of non-pennate diatoms treated include Thalassiosirales, Stephanodiscales, Paraliales, Aulacoseirales, Melosirales, Coscinodiscales and Biddulphiales. For each of the 328 taxa treated, we detail their nomenclature, systematics and spatial and temporal ranges. Severn! new combinations and two new species are described in the context of this work. We identify morphological groups within several large genera. The patterns of distribution for these taxa suggest there were worldwide invasions of freshwater in the Oligocene and Miocene across several different orders and families of these groups, and that nonmarine basin formation and high silica levels may have created new niches for certain lineages to exploit. Other patterns suggest local or regional differentiation, and extinctions, in the Miocene and Pliocene. This inventory is presented as a tool for future workers who may be interested in a wide range of topics related to ecology, evolution and changing environmental conditions.